As I understand this discipline, if one lies their pulse rate increases and blood pressure rises.  Let's assume for a moment this is true.  My question, is this:  Does the increased pulse rate cause the blood pressure to rise, or are the two phenomenon independent of each other?  If they are, what causes the blood pressure to rise?

Remember that p/g does not measure blood pressure per se, but the increase in blood volume.
But, you were going in the right direction anyway.

The greater the threat to the subject (like loss of liberty for SO's) the greater the pp response.
Unfortunately it is not only liars that experience that phenomenon, but certain truth-tellers also.

That is the fundamental problem with polygraph. Not that it does not catch liars, but that it incorrectly 'catches' truth-tellers as well. It also fails to catch a few baddies.

Yes it has a greater than chance efficacy, but what is 'CHANCE' ?
Chance is spitting against the wind. Maybe it'll hit you in the face. Maybe it wont.
Is chance 20 / 30 50 / 60 %. 
There is no definitive scale for chance.
If 'chance' was 96% then the p/g is great.
If chance is 50% then the p/g, being significantly better than chance may not be so good.
How much is "significant" ? ....20 / 30 / 40 % ??

If a p/g examiner was falsely accused of raping and killing a woman, merely because eye
witnesses saw him asking her for directions, I wonder if the examiner would be willing to submit
to a p/g exam by lets say..... Ed Gelb ?

Sergeant1107: Quote:


Correct.
 
Quote:


Not correct.

Mr. Sergeant1107,

Your syllogism and conclusion are in error here. Unless you have borrowed Mr. Maschke's magic mind-reading machine, I cannot see how you can allow yourself to speak for the feelings of polygraph examiners.

Mostly though, your argument is a reductionistic straw-man type of argument, and without substance. You should know very well by now that the polygraph employs more physiological data than simple blood pressure. Your form of argument is based on the false premise that a single index of any datastream is regarded as adequate and informative in isolation. 

As I assume you be reasonably intelligent and somewhat knowledgeable about polygraph science already. I can only conclude that you are intentionally attempting to mislead people with this false information.

Please be more careful. Providing false and inaccurate information is a violation of the post policies.

Thank you.

r

nopoly4me: Quote:


Your question seems rather obvious.

Blood pressure is mediated by pulse rate, cardiovascular contractility, and vascular tension. 

This is, of course, the bare-bones physiological explanation for the lay person.

More information about your actual concern might help elicit more useful information. Unless, perhaps you are baiting an argument. 

r

a rerun post from policehopeful's post;

Your question brings to mind the potential for a person to endure open heart surgery without anesthetic---by virtue of yogi-like self control. Perhaps it is possible, but such power over the mind and corresponding body is extroadinary---a word that is used too frequently and has lost it's meaning. A target-guilty examinee would have to be deluded, and completely detached from the oft times very intense experience of the test. Such detachment is nick-named "probably on mind altering drugs" and will merit such remarks on the report. Like getting caught attempting----or even mere suspicion of intentional countermeasures, and such a label wraps the neck with a skunk's tail. 

nopoly4me: Quote:


Through the use of a standard issue blood pressure cuff and sphygmomanometer (that's a pump-bulb and dial, to you and me).

r

nope,

You'll have to try to refrain from engaging all the anti-drama at this site. Unless that is what your here for.

The cuff is not inflated for an hour at a time. It is not even inflated with enough pressure to occlude circulation. Nobody's arm has ever fallen off during a polygraph test. 


r

Quote:


We don't score pulse rate alone, so your question doesn't make a whole lot of sense.  (There is a correlation between a HR of 100BPM or greater and deception to the relevant questions, but that's more trivia than anything.)  DACA is now looking at rate if, and only if, there is no phasic response in either channel being compared, but I can't say I've ever seen that one, and most of the research on rate changes (and it's not as simple as increasing or decreasing) use a computer to "see" such changes.

The bottom line in scoring any feature is simply asking which reaction is greater.  The bigger reaction gets the score.  That's oversimplified, I know, but it's easy.